1. Field of the Invention
The present invention generally relates to sensor network systems and, more particularly, to small sensor devices and methods for controlling small sensor devices in order to increase efficiency of the sensor network system.
2. Discussion of Background
A sensor network system consists of pervasive sensor devices attached to a multitude of different environments in our everyday world. These environments include humans, buildings, commodities, etc. In a human, for example, a sensor device may monitor heart rate, temperature, acceleration, movement of limbs, and emergency situations. In a building, for example, a sensor device may monitor seismic data, movement of structural supports, fires, and floods.
A conventional sensor network system includes sensor devices, which include individual sensors to collect sensed data from the environment in which the sensors are placed; and external applications, which reside in external devices and communicate with sensor devices via radio frequency wireless communication. Examples of an external device include a laptop computer, a personal computer, and a cellular phone. The sensors in the sensor devices collect sensed data from attached targets according to an external request from an external application. The sensed data is then sent back to the external device through wireless communication. The sensor device transmits sensed data in one format back to the external devices. The sensor device may communicate with many different external devices concurrently.
Unfortunately, sensed data that is compatible with one particular external application may not be compatible with another external application. Another problem is that power consumption requirements may be different amongst different external applications. A conventional sensor device cannot change levels of performance to match a particular application. Still another problem is that conventional sensor devices do not encode data for security before transmitting the sensed data. Also, sensor devices do not compress sensed data before the sensed data is transmitted back to the external devices. These problems combine to make the sensor network system inefficient and unduly costly to operate.